Psychoactive compounds containing heterocyclic nuclei (indoles, isoindoles, quinolines, isoquinolines, pyridine) will be chemically modified by inserting a methylene bridge adjacent to the hetero atom. This will be expected to modify physiological activity through changing the planarity of the molecules, introduction of asymmetry due to the projecting cyclopropane ring, and altering the electronic characteristics of the aromatic systems (making them homoaromatic in certain instances). The main initial thrust will be the application of chemical techniques to model systems that contain the basic heterocyclic ring. These rings must be reduced by the Birch method to yield an unconjugated, dihydro aromatic system. As in most cases, the dihydro compound can be selectively cyclopropanated using a methylene or dihalomethylene source. As appropriate, the dihalo species is readily reduced. Subsequently, rearomatization will lead to the bridged norcaradiene or cycloheptatriene type bridged compound. The hydrogens on the bridge serve as a sensitive probe into the nature of the new ring system, for their nmr chemical shifts and coupling constants reflect ring-current and electronic features of the species.